Binder for mold materials



Patented Mar. 3, 1931 MONROE S. CLAWSON, OF MON'IGLAIR, NEW JERSEY BINDER FOR MOLD MATERIALS No Drawing.

This invention relates to the metal founding art and has particular reference to a binder adapted to be used in conjunction with sand or other equivalent mold forming material for the purpose of effecting carbonization of the surfaces of the mold cavity for producing sharply defined castings.

It is well known that sand and other analogous or similar mold materials must have added thereto some sort of binder to give the mold rigidity and prevent breaking down thereof upon impingement of molten metal thereagainst. A common practice in foundry Work is to use a wet sand mold with a binder of molasses, flour, gum, or the like, the mold being of course dried out or baked after forming. Such a binder fulfills its purpose to a limited and unsatisfactory extent inasmuch as it may be considered that it is the Water 2 of crystallization which effects the binding action. As an alternative, it has been proposed to make use of a material such, for instance, as resin, linseed oil or the like as a binder but such is unsatisfactory for the reason that such materials are volatile and are driven off when the mold is baked, the result being that the mold possesses insufficient stren th and frequently, if not generally, crumfiles under strain. Attempts have also been made to make use of proteid material such as gum, saw-dust (cellulose) or many kinds of gluey substances. However, the use of these ingredients has been unsatisfactory for the reason that during the baking of the mold the proteids form a charcoal which is soft and friable.

It is with the above facts in view and to overcome the difficulties pointed out that I have designed the present invention which has for its object the provision of what may be called a desiccated binder in that it is entirely free from water or moisture and which embodies a combination of materials which will cooperate to form a strong and rigid mold and which will carbonize at the surfaces of the mold cavity for insuring smooth sharp castings, there being, moreover, no danger of breaking down of the mold.

Another object of the invention is to pro- Applloation filed August 25, 1828. Serial No. 131,543.

vide a mold material binder consisting of common ingredients which may be readily obtained at minimum cost and which may be treated and combined as required and in proper proportions in a simplemanner.

A more specific object is to provide a binder of this character embodying a desiccated proteid in powdered form in combination with a mineral oil vehicle, these materials being preferably successively added to or mixed with the molding sand, the oil producing the necessary packing effect and the combination of the materials insuring carbonization upon baking the mold.

To the attainment of the foregoing and 35 other objects and advantages, the invention preferably consists in the combination and proportion of ingredients, the method, steps and the treatment of the ingredients themselves to be hereinafter more fully described and claimed.

In carrying out the invention I have found that highl satisfactory results can be obtained by t e use of such proteid material as saw-dust, or any kind of gum or glue, to- 7 gether with a readily available substance such as resin. If a gum is used it is desiccated by boiling it in resin, the moisture in the gum being expelled and replaced by resin. The gum rises and is skimmed off, cooled and'go ground.

In case saw-dust is the proteid material used, it is dried out and then ground with resin inasumch as material such as saw-dust cannot be desiccated with resin as a sticky 5 mass would result.

Regardless of which powder is used, the additional ingredient employed is a mineral oil, parafiin oil being very suitable owing to its cheapness. In view of the fact that the desiccated gum does not take up quite enough resin to insure carbonization of the mold, I have found it advisable to add a certain amount of resin to the oil. In actual practice it has been discovered that a proper proportion is four pounds of resin to five gallons of oil, the mixing being accomplished under heat. It will thus be seen that use is made of a powder, which may be either of the two above specified, and a fluid vehicle consisting for instance of a resin, in or with a mineral oil. v

In making a mold, it is preferable that the selected powdered material be mixed with the sand or other mold material, subsequently to which the fluid material, namely oil containing resin, is added, the whole mass being.

thoroughly mixed. The mold is made in the usual manner.

Regardless of which ingredients are used and also regardless of the exact manner in which they are mixed with or applied to the molding material, the mold must be baked to harden it and make it suitable for the casting of metal therein. I have discovered that inexpensive and yet highly eflicient and easily applied and handled binding material for molds employed in casting metals, and one, moreover, which is entirely free from water or moisture and the disadvantages resulting from its presence. It is believed that the formation, treatment and employment of the binder will be readily understood by one skilled in the art without further explanation.

While I have described certain specific materials and have gone into the exact mode of treatment thereof, it should be understood that the disclosure is merely an exemplification of the principles involved, namely the employment of a desiccated proteid and a fat, and I reserve the right to make all such changes as will not depart from the spirit of "the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. A binder vfor mold materials comprising comminuted carbonizable material in the form of saw-dust and a resin together with paraflin oil in substantially the proportion of four pounds of comminuted material to five gallons of oil.

2. A binder for mold and core materials comprising saw-dust treated to remove the moisture and adapted to be mixed with a mold and core material in a dry state, and a vehicle consistin of oil having resin dissolved therein an adapted to be subsequently mixed with the mold material.

3. A binder for mold materials comprising comminuted carbonizable material in the form of dehydrated vegetable fiber, and resin dissolved in mineral oil.

4. A binder for mold materials comprising carbonizable material in the form of saw dust and resin dissolved in mineral oil.

5. A binder for mold materials com rising carbonizable vegetable matter in the orm of dehydrated saw dust and resin dissolved in parafiin oil.

6. A binder for mold and core materials. comprising vegetable fiber treated to remove the moisture and adapted to be mixed with a mold and core material in a dry state, and a vehicle comprisin oil having resin dissolved therein and a apted to be subsequently mixed with the mold material.

7. A binder for mold materials comprising carbonizable material-in the form of comminuted dehydrated vegetable fiber and a resin in a fluent state.

8. A binder for mold materials comprising carbonizable material in the form of comminuted dehydrated vegetable fiber and a resinous solution.

9. A binder for mold materials comprising comminuted carbonizable material in the form of dehydrated vegetable fiber, and a solution containing resin.

10. A binder for mold materials comprising comminuted carbonizable material in the form of dehydrated vegetable fiber, and an oleaginous liquid containing a resin.

In testimony whereof I aflix my signature.

MONROE S. CLAWSON. 

